Studies on Three-Dimensional Mixed Convection with Surface Radiation in a Rectangular Channel with Discrete Heat Sources

ABSTRACT

The flow behavior and heat transfer characteristics of conjugate heat transfer under mixed convection for a three-dimensional laminar flow in a rectangular channel with six protruding heat sources, mounted on the lower wall of the channel, have been studied numerically and experimentally. At higher temperatures, radiation plays an important role. This work reports the effect of radiation on conjugate mixed convection heat transfer. Air is taken as a cooling medium and is considered to be radiatively non-participating medium. The parameters considered for the study are positions (streamwise and spansise) of the heat sources, Reynolds number, emissivity of the heat sources, and the thermal conductivity of a printed circuit board (PCB) having constant fluid properties with the Prandtl number being 0.707. The Boussinesq approximation has been used. Commercial software ANSYS Fluent has been used for numerical analysis, and experiments have been carried out in a small-sized wind tunnel. The ranges of Reynolds number, emissivity, and thermal conductivity of PCB are 115–690 (corresponding inlet velocity of 0.25–1.5), 0–0.9, and 0.038–1.4 W/mK, respectively. Results indicate that the radiative heat transfer is significant at lower Reynolds number and lower thermal conductivity of PCB. The streamwise spacing of heat sources has larger influence compared to the spanwise spacing.

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Notes on contributors

Nitish Kumar Chaurasia

Nitish Kumar Chaurasia is an M.S. research scholar at Heat Transfer and Thermal Power Laboratory in the Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India. He has a bachelor's degree in Aeronautical Engineering from Aeronautical Society of India, New Delhi. His research interests include computational fluid dynamics studies and experimental investigations on conjugate mixed convection with surface radiation and cooling of electronic devices.

Sateesh Gedupudi

Sateesh Gedupudi is an Assistant Professor in the Department of Mechanical Engineering at Indian Institute of Technology (IIT) Madras, Chennai. He obtained his Ph.D. in Heat Transfer from IIT Madras and has done postdoctoral research in flow boiling in mini/micro-channels at Brunel University, UK. His current research interests are two-phase flow and heat transfer and non-conventional energy sources.

Shakkottai P. Venkateshan

Shakkottai P. Venkateshan is a Professor Emeritus in the Department of Mechanical Engineering, Indian Institute of Technology (IIT) Madras, India. He received his Ph.D. degree from IISc Bangalore, India, in 1977. After spending 3 years at Yale University, he joined IIT Madras in 1982. His research interests, in a broad sense, include interaction of natural convection with radiation, numerical, and experimental heat transfer, heat transfer in space application, radiation heat transfer in participating media, and instrumentation. He has been a consultant to ISRO, DRDO, and BHEL in India and NASA in the United States. He has three patents to his credit in the area of instrumentation. He has published more than 100 research papers in national and international journals and conferences, and has authored 3 textbooks. He has produced several video lecture series, including one on mechanical measurement, that are broadcast on the Eklavya Technology Channel, dedicated to technical education.